Ô tô chuyển động trên đường cong có bán kính R = 300(m). Nếu vận tốc ôtô tăng đều từ v1 =

Which state of matter is best at conducting heat?

jek_recluse [69]

Solids are the best at conducting heat.

4 0

3 years ago

Which is greater the attraction of the earth for 1 kg of aluminum or aluminum or attraction of 1kg of aluminum for the earth?

OleMash [197]

Those forces are exactly equal.

Gravity always works as a pair of <em>EQUAL</em> forces ... one in each direction
between two masses. Your weight on the Earth is exactly the same as
the Earth's weight on you.

8 0

3 years ago

The third floor of a house is 8m above street level. How much work is needed to move a 136kg refrigerator to the third floor?

jonny [76]

m = Mass of the refrigerator to be moved to third floor = 136 kg

g = Acceleration due to gravity by earth on the refrigerator being moved = 9.8 m/s²

h = Height to which the refrigerator is moved = 8 m

W = Work done in lifting the object

Work done in lifting the object is same as the gravitational potential energy gained by the refrigerator. hence

Work done = Gravitation potential energy of refrigerator

W = m g h

inserting the values

W = (136) (9.8) (8)

W = 10662.4 J

8 0

3 years ago

A ball is kicked at an angle of 35° with the ground.a) What should be the initial velocity of the ball so that it hits a target

stiks02 [169]

Answer:

a.18.5 m/s

b.1.98 s

Explanation:

We are given that

$\theta=35^{\circ}$

a.Let $v_0$ be the initial velocity of the ball.

Distance,x=30 m

Height,h=1.8 m

$v_x=v_0cos\theta=v_0cos35$

$v_y=v_0sin\theta=v_0sin35$

$x=v_0cos\theta\times t=v_0cos35\times t$

$t=\frac{30}{v_0cos35}$

$h=v_yt-\frac{1}{2}gt^2$

Substitute the values

$1.8=v_0sin35\frac{30}{v_0cos35}-\frac{1}{2}(9.8)(\frac{30}{v_0cso35})^2$

$1.8=30tan35-\frac{6574.6}{v^2_0}$

$\frac{6574.6}{v^2_0}=21-1.8=19.2$

$v^2_0=\frac{6574.6}{19.2}$

$v_0=\sqrt{\frac{6574.6}{19.2}}=18.5 m/s$

Initial velocity of the ball=18.5 m/s

b.Substitute the value then we get

$t=\frac{30}{18.5cos35}$

t=1.98 s

Hence, the time for the ball to reach the target=1.98 s

7 0

3 years ago

How long would it take to travel 10 light years at the speed of light?

Vladimir79 [104]

A light year is the DISTANCE light travels through vacuum in 1 year.

If light is traveling through vacuum, then it's traveling at the speed of light in vacuum. If a student at home at the beginning of the trip is holding the clock, then ...

Traveling 1 light year takes 1 year.

Traveling 2 light years takes 2 years.

Traveling 3 light years takes 3 years.

Traveling 10 light years takes 10 years.

If the light is traveling through some other substance, or if the clock is traveling along with the light, then these numbers all change.

YOU cannot travel at the speed of light. We have to just leave it at that

6 0

3 years ago